python调用cmd复制文件代码分享

def load() :
    filename = os.getcwd() + r'\fromto.txt'
    if os.path.isfile(filename) :       
        f = open(filename)
        try :
            lines = f.readlines()
        finally :
            f.close()
            return lines
    else :
        print('请创建fromto.txt.')
        input()
        exit()